@odedta
Thanks for your link and this reply. I think the problem will soon be solved.
Work on
writer2xhtml EPUB converter has been resumed for two months after a two and a half years break and a brand new version 1.4 beta has been released on the 22d of October. It supports already
html5 exports and will soon provide for version 1.6 a
full EPUB3 support.
http://writer2latex.sourceforge.net/index1.html
http://sourceforge.net/projects/writer2latex/
This program is written in Java and including a script inside will be authorized.
There is also a way to do it using CSS only but it does not look so easy...
http://www.wks.fr/Creer-une-popup-100-CSS.html